To my amateur eyes it looks like its so high that ground effects wont even matter?
Going too low can choke the underbody airflow, too, so there's a compromise to be had. Also, "ground effect" and "underbody aero" are actually two different mechanisms that just work together. Plus, higher ride height makes the car less sensitive to roll/dive, so sometimes more predictable handling yields faster laptimes than better grip when better grip is less predictable.
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